Often water infiltrates into tanks and reservoirs for liquid fuels such as diesel oil, kerosene and the like for feeding burners of heating installations in dwelling houses. The water tends to deposit on the bottom of the tank below the fuel and is sooner or later sucked in by the burner feed pump together with or instead of the fuel. This causes serious inconveniences which not only lead to stopping of the heating installation but also to heavy expense for repairing the damage produced by the water in the heating apparatus.
A similar problem is encountered in fuel pumps for supplying motor vehicles in which infiltrations of water occur in the fuel tanks buried below the ground. Also in this case the water accumulates on the bottom of the fuel tank and is then delivered to the motorist instead of the gasoline or other fuel.
Even if exceptional security measures are taken to prevent the water from penetrating into the fuel reservoir, water tends to accumulate nevertheless in the fuel reservoir, for example, by condensation. Once the water has condensed and precipitated on the bottom of the reservoir, it can no longer leave it except through the fuel delivery pump. Thus, the water will accumulate in the fuel reservoir up to an unacceptable amount such as to cause the aforementioned inconveniences.
It also happens that water is introduced into the fuel reservoirs intentionally by dishonest suppliers with the intention of cheating their clients who then not only do not receive the amount of fuel they have paid for, but additionally have their heating installation damaged.